the prothets truth and regret found out when they asked the oricle what species the forunners were and when the oricle told the prothets it was the humans that made him,they didnt want to tell the rest of the covenent because they had based there reldgion off of that the forunners activated halo and went to the `divine beyond" so they feared the covenent would break up if they told them that the humans were forunner so they went to war with the humans to extint them so the rest of the covent wouldnt find out and split up